Benchmark: key in object vs object.key

Script Preparation code:

var key = 'hello';
var value = 'world';
var object = {[key]: value};

Tests:

key in object
key in object
object.key
object.key

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
key in object
object.key

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.36 Edg/135.0.0.0

Browser/OS: Chrome 135 on Windows

View result in a separate tab

Test name	Executions per second
key in object	194556048.0 Ops/sec
object.key	216111216.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

I'll explain the benchmark in detail.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmark test case on MeasureThat.net. The goal of this benchmark is to compare the performance difference between two approaches when accessing a value within an object: using the dot notation (`object.key`) and using the `in` operator (`key in object`).

**Approach 1: Using Dot Notation (`object.key`)**

This approach involves directly accessing the value stored under a given key by concatenating the key to the object's name. For example, if you want to access the `value` property of an object named `myObject`, you would use `myObject.value`.

Pros:

* Generally faster and more readable
* Less error-prone than using the `in` operator

Cons:

* Only works when the key is a direct property of the object. If the object has nested properties or other complexities, this approach may not be suitable.
* Can lead to slower performance if the object's structure changes frequently.

**Approach 2: Using the `in` Operator (`key in object`)**

This approach involves using the `in` operator to check if a key exists within an object. If the key is found, it returns the corresponding value; otherwise, it returns `undefined`.

Pros:

* Works for objects with nested properties or other complexities.
* More flexible than dot notation.

Cons:

* Generally slower and less readable than dot notation.
* May lead to better performance if the object's structure remains stable.

**Library Usage**

There is no library used in this benchmark. The script preparation code only defines a simple object `myObject` with a single property `value`.

**Special JS Features/Syntax**

The benchmark does not mention any special JavaScript features or syntax that would require additional explanation. However, it's essential to note that the `in` operator and dot notation are built-in operators in JavaScript.

**Other Alternatives**

If you wanted to measure the performance difference between other approaches, such as using bracket notation (`[key]`) or accessing properties through a different object (e.g., `myObject[key]`), MeasureThat.net would allow you to create new benchmark test cases with varying script preparation codes and HTML preparation codes.

Keep in mind that the choice of approach depends on your specific use case, performance requirements, and personal coding style.

Related benchmarks:

key in object vs object.key (version: 0)

Comparing performance of: key in object vs object.key

Created: 4 years ago by: Registered User

Jump to the latest result

key in object

object.key

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):